Confidential information is stored, transmitted, and used by many electronic devices. Many such devices include components having one or more cryptographic or other secret keys, which may be used to protect the security of confidential information with encryption or other techniques. Techniques for generating these keys often include the use of a random number source. A physically unclonable function (PUF) is a desirable random number source because it may be used to provide a unique, repeatable, and unpredictable random value within an integrated circuit.